Spike glycoprotein of SARS-CoV-2 (B.1.351 variant)

The **spike glycoprotein of SARS-CoV-2 (B.1.351 variant)** is a large, trimeric, class I viral fusion protein found on the surface of the virus, responsible for mediating attachment to the host cell receptor ACE2 and subsequent fusion of the viral and host membranes[1][2][3][4][5]. The spike is composed of an S1 subunit, containing the receptor-binding domain (RBD) that recognizes ACE2, and an S2 subunit, which facilitates membrane fusion[1][3][5]. The B.1.351 ("Beta") variant is characterized by several mutations in the spike protein, including K417N, E484K, and N501Y, conferring increased binding affinity to ACE2 and significant resistance to many neutralizing antibodies[2][4]. As the principal surface antigen, the spike glycoprotein is the main target for diagnostic assays, monoclonal antibody therapeutics, and all clinically authorized COVID-19 vaccines[1][4][5]. Spike-targeted immune responses drive protection, but spike variations in B.1.351 reduce the efficacy of some antibodies and current vaccines due to immune escape[2][4]. Understanding spike structure–function and mutation impact is critical for COVID-19 therapeutic, diagnostic, and vaccine strategies[4][5].

Other names

Spike protein of SARS-CoV-2S glycoproteinS proteinSARS-CoV-2 spikeSARS-CoV-2 SS-proteinSpike glycoprotein (Beta variant)Spike protein (B.1.351)S glycoprotein (B.1.351)

Blockade of receptor-binding domain (RBD) interactions with ACE2 (preventing viral cell attachment); Inhibition of conformational changes required for membrane fusion; Induction of antibody-dependent effector functions; Vaccine-induced immune response (priming immune system to recognize spike)